simulation of a pre-compressor swirl device using gt-suite · 16/10/17 simulation of a...

16/10/17

Simulation of a pre-compressorswirl device using GT-SUITE

Anita Bongards, Dr. Wolfgang Wenzel, Jerry Song

© BorgWarner Inc. 2

pre-compressor swirl device

a.k.a. Inlet Swirl Throttle = IST

Before we start …


� Background and Motivation

� Hardware Description and Setup

� Project Layout

� Modeling Process: Necessary Input, Calibration, Challenges

� Effects on Engine at Full Load

� Summary and Outlook

Content


� New emission legislation (WLTC, RDE) requires a combination of engine internal measures and aftertreatment for NOx emission reduction.

� External EGR is used in the complete engine map.

� Low pressure EGR systems are fully established.

� Single stage TC applications move to higher torque/power.

Air System Trends – Boosting Needs

Diesel Engines

AVL


Inlet Swirl Throttle

LP-EGR Valve

Inlet Swirl Throttle

Air

Exh

. gas

Intake/ Exhaust Throttle

Inlet Guide Vanes

Turbocharger

Throttling (Diesel)

Improved LP-EGR mixing

Improved compressor performance� Efficiency� Surge behavior


Close to surge line Compressor design area Close to choke line

Pre-swirl reduces incidence angle and increases compressor speed

Negative pre-swirl increases incidence angle and reduces turbo speed

Incidence angle is ideal, no pre-swirl required

Inlet Guide Vanes – Influence on Aerodynamics


Design� Optimized flow� Modular� compact

EngineDyno testing

Hot gas bench testing� Several generations of

prototypes� Varying levels of detail

Controls development� Based on BorgWarner Air

Systems Controller� Developed in Simulink� Actuated: VTG, EGR-

valves, IST� Linked to GT for testing

GT-POWER simulation� Support test and controls

engineers� Enable further

investigations after dynotesting was finished

� Closely linked to other sub-projects

Project Layout


Modeling – Setup 1 & 2

Engine data

� 2.0 L Diesel engine� 105 kW rated Power� EPA Tier 2 Bin 5 � HP & cooled LP-EGR

LP-EGR setups

1. LP-EGR-valve, exhaust throttle, conical pipesection on intake side

2. LP-EGR-valve, IST, pipe section replacingexhaust throttle

Setup 2: IST

Setup 1: Exhaust throttle


Modeling – Detailed to Fast Running Model

72 flowvolumes

268 flowvolumes

� Simplifying model� Combining subvolumes� Re-Adjusting pressure losses

=> FRM 3-4 times faster thandetailed model


0 deg

35 deg

50 deg

75 deg

Modeling – Functions of the IST and Input

Function:

� Throttling

� Efficiency

� Surge line

� (Improved mixing)

Flow bench data

Hot gas stand data

Benefits can not besimulated currently


0 deg

35 deg

50 deg

75 deg

Modeling – Functions of the IST and Input

Function:

� Throttling

� Efficiency

� Surge line

� (Improved mixing)

GT-lookupFlow bench data

GT-cmpHot gas stand data

Benefits can not besimulated currently


Challenges with 1st IST Measurements

Measurement on Hot gas stand across wholeassembly

compressor

IST

LP-EGR

p21, T21

p12, T12

p11, T11

In the first measurementcampaign only 4 IST positionsmeasured

Changes between angles are not linear

35 deg 50 deg 75 deg

Solution: 7 different positions measuredDelta IST smaller for higher angles

Not possible to model compressorbehaviour if LP-EGR is applied!

Solution: Additional temperature &pressuresensors between IST & cmp


Full load data comparison

Dyno data

Simulation

Cone Inlet

ISTIncreased LET

Increased n-Turb

Decreased n-Turb

Increased efficiency

Positive IST-angles increasecompressor efficiency andturbocharger speed

Negative IST-angles decreaseturbocharger speed and canhelp with altitude reserves

Correlation FRM-Model to Dyno Data


Compressor maps at 1375rpm

Compressor is operating at different massflow and pressure conditions

At same pressure ratio operation without IST would lead to surge behaviour, andworse efficiency

Compressor Behaviour


� IST modelling completed with throttling & efficiency feature

� IST combines EGR enhancement function with efficiency benefits and

improves surge behaviour

� Lessons learned:

� additional measuring points at Hot gas bench testing necessary

� at least 7 IST positions necessary for acceptable simulation accuracy

� Still neglecting effects of better mixing and turbine performance

� Product development going on, samples available and being evaluated

by customers

Summary and Outlook


Thank you!

simulation of a pre-compressor swirl device using gt-suite · 16/10/17 simulation of a...

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